[Effects of different tillage measures on soil organic carbon in dryland wheat fields on the Loess Plateau, Northwest China based on meta-analysis]

To evaluate the effects of tillage measure on soil organic carbon (SOC) and influence degree of various factors on relative change rate of SOC at regional scale, we conducted a meta-analysis to investigate the impacts of tillage measures (CK, traditional deep tillage without straw return; NTS, no tillage with straw return; NT, no tillage without straw return; TS, traditional tillage with straw return; SS, subsoiling tillage) on SOC content and influence factors (climate conditions, soil types, cultivation types, and initial soil physicochemical properties) on relative change rate of SOC in dryland wheat fields on the Loess Plateau, based on literatures published during 2000-2023. Results indicated that NT, NTS, SS and TS performed varies positive effect on SOC content in 0-20 cm soil layer compared with CK. In addition, greater enhancement of SOC were obtained in conditions of loessal soil, mid-temperate zone, average annual temperature of ≤10 ℃ and average annual rainfall of ≤500 mm. It was favorable to carbon sequestration when the initial SOC ≥10 g·kg^-1, alkaline nitrogen ≥60 mg·kg^-1, available phosphorus ≥20 mg·kg^-1 and available potassium ≥120 mg·kg^-1. However, accumulation of SOC could be weakened under higher total nitrogen content (≥1 g·kg^-1). In conclusion, NTS treatment performs better carbon sequestration effect in the topsoil and can be used as suitable tillage measure in dryland wheat fields on the Loess Plateau region.